Are there preorders where this isn't the norm? Whether you're camped out for the latest iPhone or preordering some hot new game, it's always understood that your place in line is a major factor in when you get your product but it's not a guarantee and the ordering isn't strict.
I'm baffled at why anyone would think it should be otherwise. Guaranteeing a strict order would be essentially impossible, and it would mean that a problem with a single unit would delay the entire group of people behind it.
It wouldn't surprise me if this becomes the norm in any 'place in line' list with high value items. Companies would love the ability to offer the chance to consumers to put a down payment for a place in line while at the same time removing any liability in case they have to break that agreement.